Lowell Observatory Colloquia

Adaptive optics for direct imaging of exoplanets

Katie Morzinski, Steward Observatory

Lowell Observatory, Giclas Lecture Hall, 29 March, 2012 at 3:30 p.m.

Imaging exoplanets is limited by scattered light from the parent star. Adaptive optics (AO) can be used in real time to reduce the seeing halo. However, residual wavefront error results in constructive-interference "speckles" in the image plane. Accurately determining the PSF (point-spread function) allows for speckle subtraction, revealing the planet in software. Second-generation instruments such as the Gemini Planet Imager (GPI) and Magellan's "MagAO" further suppress diffraction to reduce the residual wavefront error and speckle incidence in hardware. I will describe high-order wavefront control in GPI and MagAO, both to go on-sky in Chile in the next year. I will also discuss the popular LOCI (locally-optimized combination of images) algorithm for PSF determination, and show its application in a snap-shot survey with Keck AO for brown dwarf companions to 85 Hyads. The development of high-order AO capabilities indicates that exoplanetary system HR 8799 is the harbinger of many more systems to be directly imaged with instruments such as GPI and MagAO.

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